XRP6670
3A 300kHz-2.5MHz Synchronous Step Down Regulator
June 2013
Rev. 1.0.1
GENERAL DESCRIPTION
The XRP6670 is a synchronous current mode
PWM step-down (buck) regulator capable of
delivering up to 3 Amps. A 2.6V to 5.5V input
voltage range allows for single supply
operation from industry standard 3.3V and 5V
power rails.
Based on a current mode PWM control
scheme, the XRP6670 operating frequency is
programmable between 300kHz and 2.5MHz
via an external resistor. This flexibility allows
the XRP6670 to optimize component selection
and reduce component count and solution
footprint. It provides a low output voltage
ripple, excellent line and load regulation and
has a 100% duty cycle LDO mode. Output
voltage is adjustable to as low as 0.8V with a
better than 2% accuracy while a low quiescent
current supports the most stringent battery
operating conditions.
Built-in over-temperature, overcurrent, short
circuit and under-voltage lock-out protections
insure safe operations under abnormal
operating conditions.
The XRP6670 is offered in a RoHS compliant,
“green”/halogen free 3mmx3mm 10-pin DFN
package.
APPLICATIONS
•
Industrial & Medical Equipment
•
Audio-Video Equipment
•
Networking & Telecom Equipment
•
Portable/Battery Operated Equipment
FEATURES
•
Guaranteed 3A Output Current
−
Input Voltage: 2.6V to 5.5V
•
Prog. PWM Current Mode Control
−
Programmable 300kHz to 2.5MHz
−
100% Duty Cycle LDO Mode Operation
−
Achieves 95% Efficiency
•
Adjustable Output Voltage Range
−
0.8V to 5V with ±2% Accuracy
•
Enable and Power Good Functions
•
460µA Quiescent Current
•
Over-temperature, Over-current,
Short-circuit and UVLO Protections
•
RoHS Compliant “Green”/Halogen Free
3mm x 3mm 10-Pin DFN Package
TYPICAL APPLICATION DIAGRAM
Fig. 1: XRP6670 Application Diagram
Exar Corporation
48720 Kato Road, Fremont CA 94538, USA
www.exar.com
Tel. +1 510 668-7000 – Fax. +1 510 668-7001
XRP6670
3A 300kHz-2.5MHz Synchronous Step Down Regulator
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of
the device at these ratings or any other above those
indicated in the operation sections of the specifications
below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect
reliability.
V
DD
, PV
DD
, FB, COMP, SHDN/RT ................... -0.3V to 6.0V
SW ................................................... -0.3V to V
DD
+0.3V
Junction Temperature Range............................... +150°C
Storage Temperature .............................. -65°C to 150°C
Power Dissipation ................................ Internally Limited
Lead Temperature (Soldering, 10 sec) ................... 260°C
ESD Rating (HBM - Human Body Model) .................... 2kV
ESD Rating (MM - Machine Model) ...........................200V
OPERATING RATINGS
Input Voltage Range V
IN
............................... 2.6V to 5.5V
Maximum Output Current (Min.) .................................3A
Junction Temperature Range ................. -40°C to +125°C
Thermal Resistance ......................................................
DFN10 θ
JA
....................................................110°C/W
DFN10 θ
JC
....................................................... 3°C/W
Note 1: T
J
is a function of the ambient temperature T
A
and
power dissipation P
D
: (T
J
= T
A
+ (P
D
* θ
JA
))
ELECTRICAL SPECIFICATIONS
Specifications are for an Operating Junction Temperature of T
A
= T
J
= 25°C only; limits applying over the full Operating
Junction Temperature range are denoted by a “•”. Minimum and Maximum limits are guaranteed through test, design, or
statistical correlation. Typical values represent the most likely parametric norm at T
J
= 25°C, and are provided for reference
purposes only. Unless otherwise indicated, V
DD
= V
PVDD
= 3.3V, T
A
= T
J
= 25°C.
Parameter
Supply Current
Shutdown Supply Current
Under Voltage Lockout (UVLO)
Threshold
Under Voltage Lockout (UVLO)
Hysteresis
Feedback Voltage V
FB
FB Pin Bias Current
Current Sense Transresistance
Switching Leakage Current
Error Amplifier Voltage Gain
Error Amplifier Trans-
conductance
RT Pin Voltage
Switching Frequency Range
Maximum Duty Cycle
Minimum On-Time
Switch Current Limit
Switching FET On Resistance
Synchronous FET On Resistance
Shutdown Threshold
PGOOD Voltage Range
PGOOD Pull Down Resistance
Output Current
Output Voltage Line Regulation
Output Voltage Load Regulation
Soft Start Time
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
3
0.4
±0.2
1.5
160
20
-15
3.2
0.760
0.3
0.8
100
120
4.2
0.11
0.11
V
DD
-0.7
0.16
0.17
V
DD
-0.4
+15
120
150
1
800
800
0.800
0.840
2.5
1.2
%
ns
A
Ω
Ω
V
%
Ω
A
%/V
%
ms
°C
°C
V
DD
= 2.6V to 5.5V, V
OUT
= 2.5V
V
DD
= 2.7V to 5.5V, I
OUT
= 100mA
I
OUT
= 10mA to 3A
I
OUT
= 10mA
V
FB
=0.75V
I
SW
=500mA
I
SW
=500mA
0.784
2.2
300
0.800
0.1
0.2
1
0.816
0.4
Min.
Typ.
460
1
Max.
Units
µA
µA
V
mV
V
µA
Ω
µA
V/V
µA/V
V
MHz
Programmed via R
OSC
R
OSC
=330kΩ
V
FB
=0.75V
SHDN/RT=V
DD
=5.5V
Conditions
V
FB
=0.75V, No switching
SHDN/RT=V
DD
=V
PVDD
=5.5V
V
DD
rising
© 2013 Exar Corporation
2/13
Rev. 1.0.1
XRP6670
3A 300kHz-2.5MHz Synchronous Step Down Regulator
BLOCK DIAGRAM
Fig. 2: XRP6670 Block Diagram
PIN ASSIGNMENT
Fig. 3: XRP6670 Pin Assignment
© 2013 Exar Corporation
3/13
Rev. 1.0.1
XRP6670
3A 300kHz-2.5MHz Synchronous Step Down Regulator
PIN DESCRIPTION
Name
SHDN/RT
Pin Number
1
Description
Shutdown and Oscillator resistor input.
Connect a resistor to GND from this pin to set the switching frequency. Forcing this pin
to VDD shuts down the device.
Signal ground.
All small-signal ground, such as the compensation components and exposed pad should
be connected to this, which in turn connects to PGND at one point.
Power switch output pin.
This pin is connected to the inductor.
Power Ground Signal.
Connect this signal as close as possible to the input and output capacitors C
IN
and C
OUT
.
Power Input Supply Pin.
Decouple this pin to PGND (pin 5) with a capacitor.
Signal Input Supply Pin.
Decouple this pin to GND (pin 2) with a capacitor. Typically, VDD and PVDD are
connected together.
Power Good Flag.
This is an open drain output and is pulled to ground if the output voltage is out of
regulation.
Feedback pin.
An external resistor divider connected to FB programs the output voltage.
Compensation pin.
This is the output of transconductance error amplifier and the input to the current
comparator. It is used to compensate the control loop. Connect an RC network form this
pin to GND.
Connect to GND signal (pin 2).
GND
SW
PGND
PVDD
VDD
2
3, 4
5
6
7
PGOOD
FB
8
9
COMP
Exp. Pad
10
Exp. Pad
ORDERING INFORMATION
Part Number
Junction
Temperature
Range
-40°C≤T
J
≤+125°C
Marking
Package
Packing
Quantity
3K/Tape & Reel
Note 1
Note 2
XRP6670EHTR-F
XRP6670EVB
6670
YYWW
XXX
XRP6670 Evaluation Board
DFN10
Halogen Free
“YY” = Year – “WW” = Work Week – “X” = Lot Number; when applicable.
© 2013 Exar Corporation
4/13
Rev. 1.0.1
XRP6670
3A 300kHz-2.5MHz Synchronous Step Down Regulator
TYPICAL PERFORMANCE CHARACTERISTICS
All data taken at V
IN
= V
DD
= V
PVDD
= 3.3V, T
J
= T
A
= 25°C, unless otherwise specified - Schematic and BOM from Application
Information section of this datasheet.
Fig. 4: Supply Current Versus Input Voltage
Fig. 5: Supply Current versus Ambient Temperature
Fig. 6: Efficiency versus Output Current
Fig. 7: PMOS RDS
ON
Resistance versus Ambient Temperature
Fig. 8: NMOS RDS
ON
Resistance versus Ambient Temperature
Fig. 9: Frequency versus Ambient Temperature
© 2013 Exar Corporation
5/13
Rev. 1.0.1
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